Several compounds among the compounds containing a dicyanopyrazine skeleton having an electron donating group are useful as electron transport materials, charge generating materials, optical recording materials, photoelectric conversion materials, luminescent materials, and the like.
For example. Patent Document 1 discloses an organic solid fluorescent substance containing N, N, N′, N′-tetrakis (2-methylbenzyl)-2,5-diamino-3,6-pyrazinecarbonitrile crystal represented by formula (1), of which the maximum reflectance in a visible light region by a reflectance measurement of a post-dispersive spectroscopy is 100% or more.

Patent Document 2 discloses a film obtained by adding a compound containing a quinoxaline skeleton represented by formula (3) or 2,3-dicyanopyrazine skeleton represented by formula (4) to 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile represented by formula (2). The film seems to be usable for organic electronic devices such as organic electroluminescence devices, organic thin film solar cells or the like.

Patent Document 3 discloses an organic electroluminescence device having a layer containing a dicyanopyrazine compound represented by formula (5) between an anode and cathode which are opposite to each other.

In formula (5), R1 and R2 each independently represent a heterocyclic group which may have a substituent or a hydrocarbon ring group which may have a substituent.)
Patent Document 4 discloses a compound represented by formula (6) or the like. The compound seems to be used for electron transport materials, charge generating materials, optical recording materials, photoelectric conversion materials, and the like.

Patent Documents 5 and 6 disclose compounds represented by formula (7), Formula (8) and the like. These compounds seem to be usable for functional materials such as electroluminescence and wavelength conversion material or the like.

Patent Document 7 discloses a luminescent material including a compound in which a cyano pyridine as an electron attractive site and a heteroaryl group as an electron donating site are bonded.
There are various methods for producing a compound containing a dicyanopyrazine skeleton having an electron donating group. In order to obtain a compound containing a dicyanopyrazine skeleton having an electron donating group at a low cost and in a high yield, it is necessary to investigate starting materials and intermediates. Various candidates for starting materials or intermediates are conceivable. For example, a pyrazine compound having an amino group and a cyano group, such as 6-aminopyrazine-2,3,5-tricarbonitrile, 5,6-diaminopyrazine-2,3-dicarbonitrile, 3,5-diaminopyrazine-2,6-dicarbonitrile, 3,6-diaminopyrazine-2,5-dicarbonitrile or the like can be synthesized from a diamino maleonitrile or a homolog thereof as a starting material (see Non-Patent Document 2, Patent Document 8, Patent Document 9, etc.).
As the pyrazine compound having an amino group and a halogeno group, for example, 2-amino-6-chloropyrazine, 2-amino-5-chloropyrazine, 2-amino-5-bromopyrazine and 2-amino-3,5-dibromopyrazine are commercially available and readily available. The 2-amino-bromopyrazines are likely to be synthesized by a method of reacting 2-aminopyrazines having at least one hydrogen atom in the pyrazine nucleus with bromine in the presence of a dehydrobromide agent in a solvent (Patent Document 11). This bromination is a substitution reaction of hydrogen to bromine.
As the pyrazine compound having a cyano group and a bromo group, for example, 2,5-dicyano-3,6-dibromopyrazine can be prepared from 2-cyano-3-aminopyrazine in a 4-step reaction or from 2-cyano-3-amino-6-bromopyrazine in 3-step reaction (Non-Patent Document 1). 2-cyano-3-aminopyrazine can be obtained by a method described in Non-Patent Document 3. A multi-step reaction is required for the synthesis of a pyrazine compound having a cyano group and a bromo group.
